Crown Castle International (CCI)

In connection with your review of the information set forth in this report, you
should carefully consider the factors discussed in Part 1, Item 1A. Risk Factors in our annual report on Form 10-K for the year ended December 31, 2005 and our other filings with the SEC. In addition to the factors discussed in our
annual report on Form 10-K, additional risks and uncertainties related to contemplated Global Signal Merger should be considered including those discussed below.

The assets of Global Signal to be acquired in the merger may not perform as expected, which could have an adverse effect on the business, financial condition or results of operations of the combined company.

In evaluating the anticipated benefits of a potential transaction with Global Signal, we performed due diligence on Global
Signals tower portfolio and other assets to be acquired in the merger, which due diligence included, among other things, analyzing tower locations, visiting select tower sites, evaluating radio frequency information, and evaluating potential
carrier customer demand. The results of this due diligence were used to support assumptions that were made by us in creating financial models to evaluate the potential future performance of Global Signals assets and the combined company. There
can be no assurances, however, that the towers and other assets of Global Signal will perform as expected by us based on its due diligence and provide the combined company with the benefits that have been anticipated. A variety of factors could
cause these assets not to provide such benefits, including, among other things:

local and state restrictions on the ability to modify such towers; and



latent structural weaknesses associated with such towers and the related cost of repairing, reinforcing or upgrading them.

If Global Signals assets fail to perform as expected or the combined company fails to otherwise realize the anticipated benefits of Global
Signals assets for these or other reasons, the business, financial condition or results of operations of the combined company could be adversely affected.

The Global Signal Merger is subject to waiting periods, and the receipt of consents and approvals from, or challenge by, various governmental entities, which may impose conditions on, jeopardize or delay
consummation of, or reduce the anticipated benefits of the merger.

Completion of the merger is conditioned upon the receipt of any
material governmental consents and approvals, including (i) the review of the transactions related to the merger by the Antitrust Division of the Department of Justice (DOJ) and the Federal Trade Commission (FTC), and
the expiration or termination of the applicable statutory waiting period, and any extension thereof, under the Hart Scott Rodino Act of 1976 and (ii) approval by the FCC of any transfer to the surviving company of control over FCC licenses
currently held or controlled by Global Signal.

At any time before or after the effective time of the merger, the DOJ, the FTC or others
(including states and private parties) could take action under the antitrust laws, including seeking to prevent the merger, to rescind the merger or to conditionally approve the merger upon the divestiture of assets. There can be no assurance that a
challenge to the merger on antitrust grounds will not be made or, if a challenge is made, that it would not be successful.

These consents and approvals may impose conditions on, or require divestitures relating to, either or
both of our or Global Signals divisions, operations or assets that could have an adverse effect on us or the combined company. These conditions or divestitures may jeopardize or delay completion of the merger or may reduce the anticipated
benefits of the merger. Further, no assurance can be given that the required consents and approvals will be obtained or that the required conditions to closing will be satisfied. In addition, if all required consents and approvals are obtained and
the conditions are satisfied, no assurance can be given as to the terms, conditions and timing of the approvals or that they will satisfy the terms of the merger agreement.

The Global Signal Merger is subject to certain conditions to closing that could result in the merger being delayed or not consummated, which could
negatively impact our stock price and future business and operations.

Failure to consummate the merger could negatively impact our
stock price and future business and operations. The merger is subject to customary conditions to closing, as set forth in the merger agreement. If any of the conditions to the merger is not satisfied or, where waiver is permissible, not waived, the
merger will not be consummated. Any delay in the consummation of the merger or any uncertainty about the consummation of the merger could adversely affect the future businesses, growth, revenues and results of operations of either or both of the
companies or the combined company. We can make no assurances that the merger will be consummated, that there will not be a delay in the consummation of the merger, that the merger will be consummated on the terms contemplated by the merger agreement
or that the benefits of the merger will be the same as those anticipated.

Whether or not the Global Signal Merger is consummated,
the announcement and pendency of the merger could cause disruptions in our business, which could have an adverse effect on our businesses and financial results.

Whether or not the merger is consummated, the announcement and pendency of the merger could cause disruptions in or otherwise negatively impact our business. Among other things:



the business combination of Global Signal and us may disrupt business relationships with current customers, who may delay or defer decisions about current and future agreements with
us because of the pending merger;



our current and prospective employees may experience uncertainty about their future roles with the combined company, which might adversely affect our ability to retain key managers
and other employees; and



the attention of our management may be directed from business operations toward the consummation of the merger.

These disruptions could be exacerbated by a delay in the consummation of the merger or termination of the merger agreement and could have an adverse
effect on our business and financial results if the merger is not consummated or the business and financial results of the combined company if the merger is consummated.

If the Global Signal Merger is not consummated, we will have incurred substantial costs that may adversely affect our financial results and operations and the market price of our common stock.

We have incurred and will continue to incur substantial costs in connection with the proposed merger. These costs are primarily
associated with the fees of our attorneys, accountants and financial advisors. In addition, we have diverted significant management resources in an effort to consummate the merger and are subject to restrictions contained in the merger agreement on
the conduct of our business. If the merger is not consummated, we will have incurred significant costs, including the diversion of management resources, from which we will have received little or no benefit. Also, if the merger is not consummated
under certain circumstances specified in the merger agreement, Global Signal or we may be required to pay the other party a termination fee of $139.0 million.

In addition, if the merger is not consummated, we may experience negative reactions from the financial markets and our collaborative partners, customers and employees. Each of these factors may adversely affect the
trading price of our common stock and/or our financial results and operations.

The integration of Global Signal following the Global Signal Merger is expected to result in
substantial expenses and may present significant challenges.

We may face significant challenges in combining Global Signals
operations in a timely and efficient manner and retaining key Global Signal personnel. This integration will be complex and time-consuming. The failure to successfully integrate Global Signals business and to manage the challenges presented by
the integration process successfully, including the retention of key Global Signal personnel, may result in the combined company and its stockholders not achieving the anticipated potential benefits of the merger.

Achieving the benefits of the merger will depend in part on the integration of Global Signals operations, wireless communications tower portfolio
and personnel in a timely and efficient manner and the ability of the combined company to realize the anticipated synergies from this integration. This integration may be difficult and unpredictable for many reasons, including, among others, the
size of Global Signals wireless communications tower portfolio and because our and Global Signals internal systems and processes were developed without regard to such integration. Successful integration of Global Signal also requires
coordination of different personnel, which may be difficult and unpredictable because of possible cultural conflicts and differences in policies, procedures and operations between the companies and the different geographical locations of the
companies and their assets. If the integration is not successful, the combined company might not realize the expected benefits of the merger, which could adversely affect the combined companys business and the value of our common stock after
the merger.

We may incur substantial expenses in connection with the integration of the business, policies, procedures, operations and
systems of Global Signal. There are a large number of systems that must be integrated, including management information, accounting and finance, sales, billing, payroll and benefits, lease administration systems and regulatory compliance.

Although we expect that the realization of efficiencies related to the integration of the Global Signal business may offset incremental
transaction, merger-related and restructuring costs over time, no assurances can be made that this net benefit will be achieved in the near term, or at all, and there are a number of factors, some of which are beyond the combined companys
control, that could affect the total amount or the timing of all of the expected integration expenses.

The issuance of shares of our
common stock in conjunction with the Global Signal Merger will dilute the aggregate voting power of current stockholders.

If it is
completed, the merger will dilute the ownership position of our current stockholders. Based on the number of shares of Global Signal common stock outstanding and the number of shares of our common stock outstanding, in each case on a fully-diluted
basis, as of October 31, 2006, and depending on the aggregate amount of cash consideration that Global Signal stockholders elect to receive in the merger, a maximum of approximately 114.8 million, and a minimum of approximately
98.9 million, shares of Crown Castle common stock, on a fully-diluted basis, will be issued in the merger. Immediately after the merger, Global Signal stockholders will own between approximately 33% and 36% including Global Signal options and
warrants, and Crown Castle stockholders will own between approximately 64% and 67% of the then outstanding shares of Crown Castle common stock on a basic basis. On a fully-diluted basis, Global Signal stockholders will own between approximately 31%
and 34%, and Crown Castle stockholders will own between approximately 66% and 69% of the then-outstanding shares of Crown Castle common stock, in each case on a fully-diluted basis.

The following factors could affect our future results or cause actual results to
vary materially from those described in our forward-looking statements. In addition to the information set forth in this report, you should carefully consider the factors discussed in Part 1, Item 1A Risk Factors in our annual report on
Form 10-K for the year ending December 31, 2005 and our other filings with the SEC.



Our business depends on the demand for wireless communications and towers, and we may be adversely affected by any slowdown in such demand.



The loss or consolidation of, network sharing among or financial instability of any of our limited number of customers may materially decrease revenues.



Consolidations and mergers in the wireless industry could decrease the demand for our towers and may lead to reductions in our revenues and our ability to generate positive cash
flows.



An economic or wireless telecommunications industry slowdown may materially and adversely affect our business (including reducing demand for our towers and network services) and the
business of our customers.



Our substantial level of indebtedness may adversely affect our ability to react to changes in our business and limit our ability to use debt to fund future capital needs.



We operate in a competitive industry, and some of our competitors have significantly more resources or less debt than we do.



Technology changes may significantly reduce the demand for site leases and negatively impact the growth in our revenues.



3G and other technologies may not deploy or be adopted by customers as rapidly or in the manner projected.



We generally lease or sublease the land under our towers and may not be able to extend these leases.



We may need additional financing, which may not be available, for strategic growth opportunities.



Restrictive covenants in our debt instruments may limit our ability to take actions that may be in our best interests.



Modeos business has certain risk factors different from our core tower business, including an unproven business model, and may fail to operate successfully and produce results
that are less than anticipated. In addition, Modeos business may require additional financing which may not be available.



FiberTowers business has certain risk factors different from our core tower business, including an unproven business model, and may produce results that are less than
anticipated, resulting in a write off of all or part of our investment in FiberTower. In addition, FiberTowers business may require additional financing which may not be available.



Laws and regulations, which may change at any time and with which we may fail to comply, regulate our business.



We are heavily dependent on our senior management.



Our network services business has historically experienced significant volatility in demand, which reduces the predictability of our results.

We may suffer from future claims if radio frequency emissions from wireless handsets or equipment on our towers or our equipment on other sites are demonstrated to cause negative
health effects.



Certain provisions of our certificate of incorporation, bylaws and operative agreements and domestic and international competition laws may make it more difficult for a third party
to acquire control of us or for us to acquire control of a third party, even if such a change in control would be beneficial to our stockholders.



Sales or issuances of a substantial number of shares of our common stock may adversely affect the market price of our common stock.



Our participation or failure to participate in a tower industry consolidation may be harmful to our business.



Disputes with customers and suppliers may adversely affect results.



We may suffer losses due to exposure to changes in foreign currency exchange rates relating to our operations in Australia.